At one of my first jobs I negotiated two raises into less hours (i.e. taking less hours instead of more money), so going from 40 hours/week to 36 hours/week and then 32 hours/week for the same salary.
For me the change from 40 to 36 was more significant, in that that was enough to schedule all my errands on the one afternoon per week I was off, ensuring that my weekend was always a real weekend with time to relax and hang out with friends.
Even stuff where your employer should just give you time off for (e.g. going to the dentist and stuff like that), is just less hassle if you can just schedule that in your errand day/afternoon.
For me the change from 40 to 36 was more significant, in that that was enough to schedule all my errands on the one afternoon per week I was off, ensuring that my weekend was always a real weekend with time to relax and hang out with friends.
Even stuff where your employer should just give you time off for (e.g. going to the dentist and stuff like that), is just less hassle if you can just schedule that in your errand day/afternoon.